A distinctive feature of all ZIMO function decoders is the programmable SECOND ADDRESS (CV #64 to #68), which can be used as an alternate address for passenger cars containing a function decoder.

The SECOND ADDRESS is commonly set to the same address as the loco pulling the train. If all cars in the train are equipped with decoders using the same SECOND ADDRESS, they can all be controlled simultaneously with a single key stroke (i.e. the interior light of all coaches are turned ON/OFF with a function key of the loco address).

The ZIMO SECOND ADDRESS makes the simplest form of a virtual “train bus” a reality, and will certainly play a major role in future digital train technology.

ZIMO MX681 DCC Decoders offer the following features:

The MX681 is the "sub-micro model" for Z, N and HO scale function control in the ZIMO decoder range. This remarkably small decoder comes in a variety of formats and has 6 normal function outputs.

This model does not have dedicated circuitry for external energy storage. It does have common and ground connections to easily attach additional capacitance, especially important for flicker free lighting and error free operation.

The combination of features and size makes it an effective solution for nearly any installaion project in any scale, Z through HO.

Multiple CV sets, predefined or self-defined: by storing more than one CV set, a locomotive can quickly and easily be changed for various duties that require different CV settings (i.e. single locomotive or consist, layout at home or club etc.)

User Updatable - Install the latest firmware yourself, in minutes, at no charge and without opening the locomotive. All ZIMO decoders come with this feature (including function and accessory decoders). The new firmware is always available at no charge from the ZIMO or ZIMODCC web site. (Requires MX10, MXULFA, or other device)

ZIMO Safety Features:

Reliable high voltage protection and short circuit protection for motor and function outputs.

Models available for use with track voltage up to 35 V (MX644, MX699).

ZIMO Control Features:

Special circuitry to prevent interference from capacitors, choke coils, which are often found on motors. In some cases removal of these components may still be beneficial (See Decoder Manual).

Uninterrupted operation (no stalling, stopping and new startup) during continuity interruptions of up to 1 second. All current models of ZIMO decoders have Common (+) and Ground (-) pads available for adding external capacitors. Many ZIMO decoders have special circuitry for adding external capacitors (SPEIKOMP, SPEIGOMP) which minimizes programming interference.

Uninterrupted operation on dead track sections. The decoder firmware prevents the loco from stopping when track power is lost, even while the loco is coming to a scheduled stop. This ensures that the loco can start up again even after the capacitors dissipated the stored electricity. Note: Requires external energy storage module MXSPEIK or MXSPEIG, other similar products or self-made modules connected to the decoder.

SUSI interface for the connection of other external modules, most often sound modules.

NMRA function mapping.

ZIMO Free Function Mapping procedure (CV #61=98) enables mapping of any output to any function key, directional or non-directional, which is not possible with NMRA function mapping.

ZIMO Swiss Function Mapping (CV #61=...) for special cases such as direction dependent taillights and cab light in Swiss engines.

Numerous special effects:

Soft start for function outputs

Function output dimming

Function dependent low/high beam

Adjustable flasher

Stop light logic

Output time-out function

Firebox Flicker

Speed and load dependent smoke generation and fan control

All US lighting effects

Mars Light

Rotary Beacon

Strobe and Double Strobe

Gyra Light

Ditch Light - Type I and II

Variable cycle times and minimum dim values.

Special CVs for automatic uncoupling (aka The ZIMO Coupler Waltz). After pressing the function key defined for this action, the loco backs up a few millimeters to unload the couplers then actuates the uncoupler and moves forward away from the train. The distance the loco backs-up and moves forward as well as the loco speed step is definable with CVs.

Note: On some decoders, the same function outputs can be used as either logic-level, servo or SUSI outputs.

ZIMO Common Function Outputs (a.k.a. Logic Level Outputs):

The common function output, also called a "Logic Level" output or "unamplified" output, refers to the voltage level at the terminal (0V for "off", 5V for "on"). The funtion output has an internal protection resistor equal to 10K Ohms resulting in 0.5 mA maximum available output current.

The use of the common function outputs is determined with CV settings:

CV # 124:

Bit 7 = 0 -> SUSI

Bit 7 = 1 -> Logic Level

CV's # 181, 182

If set, the common function outputs are used for servo control.

Logic Level Outputs of [C] and [D] Types:

In all decoders with 21-pin "MTC" interface (either a [C] - type or a [D] - type, e.g. MX634C MX634D or MX644C); the two variations differ in the execution of function outputs FA3 and FA4:

"D" - Outputs FA3 and FA4 are "normal" amplified outputs

"C" - Outputs FA3 and FA4 are "logic level" outputs

Note: Logic-level outputs can power one LED or any other load by using an external amplifier (i.e. M4000Z)."Logic Level" outputs can be amplified by adding the ZIMO M4000Z Logic Level Function Amplifier or similar devices.

CAUTION: "Logic Level" outputs are NOT active in the default configuration of the decoder because they use the same ports as the SUSI interface (clock and data) as well as the servo-control lines.